JP2023539901A - Rubber compositions based on highly saturated diene elastomers - Google Patents

Abstract

The present invention provides a rubber composition comprising at least a copolymer containing more than 50 phr of ethylene units and 1,3-diene units, wherein the ethylene units in the copolymer account for more than 50 mol% of the monomer units of the copolymer. Correspondingly, the elastomeric matrix is a 1,3-dipole compound corresponding to the formula "Q-Sp-B", where Q contains a dipole containing at least and preferably one nitrogen atom, and Sp is preferably a divalent atom or atomic group bonding Q to B, and B contains a specific imidazole ring), a filler containing mainly silica, and at least one radical It relates to a rubber composition based on a crosslinking system containing a polymerization initiator and a co-crosslinking agent selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds and mixtures thereof.

Description

The field of the invention is that of diene rubber compositions reinforced with inorganic fillers, such as silica, which can be used in particular in the production of vehicle tires. The field of the invention is more particularly to treads for pneumatic or non-pneumatic tires with improved rolling resistance/wear compromise.

Since the need for fuel efficiency and environmental protection has become a priority, mixtures in the form of rubber compositions can be used for the production of various semi-finished products, for example in the composition of pneumatic or non-pneumatic tires, e.g. treads. It is desirable to produce mixtures that have good anti-wear properties, while having as small a hysteresis as possible, in order to be able to process.
In order to reduce rolling resistance, it is known to use diene rubber compositions reinforced with inorganic fillers, such as silica. Diene rubber compositions reinforced with inorganic fillers usually contain silanes as coupling agents, such as polysulfides, or block mercaptosilanes, which are silanes with protected thiol groups. The silane can create an interaction between the diene elastomer and the inorganic filler and promote the dispersion of the inorganic filler in the rubber composition.

Furthermore, in order to obtain the optimum reinforcing properties provided by the filler in the rubber composition, and thus the high abrasion resistance, this filler must be as finely divided as possible and as homogeneously distributed as possible in the final form. It is known that its presence in an elastomeric matrix is usually desirable. However, such a situation is possible if this filler has a very good ability, on the one hand, to not be incorporated into the matrix and lump together during mixing with the elastomer, and on the other hand, to disperse homogeneously in this matrix. can only be achieved. As is well known, carbon black has this ability. On the other hand, this is usually not the case for inorganic fillers, especially silica. This is because, for reasons of mutual affinity, these inorganic filler particles tend to aggregate in the elastomeric matrix. These interactions theoretically result in the dispersibility of the filler and hence its reinforcing properties, if all (inorganic filler/elastomer) bonds that can occur during the mixing operation are actually obtained. It has the negative effect of limiting it to levels much lower than possible. These interactions further tend to increase the consistency of the uncured rubber compositions, thereby making their processability more difficult than in the presence of carbon black.
Therefore, it remains difficult to develop compositions filled with silica as a filler that have both excellent rolling resistance and good wear resistance.

It was possible to improve this performance compromise in tire treads by using new rubber compositions reinforced with inorganic fillers, in particular highly dispersed specific silicas. This silica can be comparable to conventional tire-grade carbon black in terms of reinforcement, while giving these compositions more, which is synonymous with lower rolling resistance for tires containing these compositions. Provides small hysteresis. Treads filled with such highly dispersed silica (denoted as "HD" or "HDS" for "highly dispersed" or "highly dispersed silica") reduce the amount of energy provided to the user. It can be used in tires with low rolling resistance, sometimes referred to as "green tires" in connection with economy ("green tire concept"), and has been widely described. Especially EP501227, EP692492, EP692493, EP735088, EP767206, EP786493, EP881252, WO99/02590, WO99/02601, WO99/02602, WO99/06480, WO00/05300, WO0 Reference may be made to patent application no. 00/05301. These prior documents teach the use of HD silica with a BET specific surface area between 100 and 250 m ² /g. In fact, one HD silica with a high specific surface area listed in the field of "green tires" is, in particular, Zeosil 1165 MP silica sold by Solvay (corresponding to a BET surface area of about 160 m ² /g). It is. By using this Zeosil 1165 MP silica, a good compromise can be obtained in terms of tire performance, in particular in terms of sufficient wear resistance and rolling resistance.

However, there remains a need to further improve the performance compromise between wear resistance and rolling resistance.
Continuing their research, Applicants have demonstrated that the above-mentioned We have unexpectedly discovered that it is possible to further improve the performance compromises made.

One object of the invention is therefore a rubber composition comprising at least
an elastomeric matrix comprising a copolymer containing more than 50 phr of ethylene units and 1,3-diene units, wherein the ethylene units in the copolymer represent more than 50 mol% of the monomer units of the copolymer;
1,3-dipole compound corresponding to formula (I),
Q-Sp-B (I)
(In the formula,
Q contains a dipole containing at least and preferably one nitrogen atom;
Sp is preferably a divalent atom or atomic group bonding Q to B,
B contains an imidazole ring corresponding to the following formula (II)

(II)
（式中、
４つの符号Ｚ、Ｙ、Ｒ及びＲ’のうちの３つは、同一であるか又は異なっており、それぞれ原子又は原子団を表し、Ｚ及びＹは、それらが連結する炭素原子と共に環を形成することができ、
且つ第４の符号Ｚ、Ｙ、Ｒ又はＲ’は、Ｓｐへの直接の連結を示す））
主にシリカを含有するフィラー、並びに
少なくとも１種のラジカル重合開始剤と、（メタ）アクリレート化合物、マレイミド化合物、アリル化合物、ビニル化合物及びそれらの混合物からなる群から選択される共架橋剤とを含有する架橋系をベースとした、ゴム組成物である。
本発明の別の対象は、本発明による組成物を含有するゴム物品、特に空気式又は非空気式タイヤのトレッドである。

(II)
(In the formula,
Three of the four symbols Z, Y, R and R' are the same or different and each represents an atom or an atomic group, and Z and Y form a ring together with the carbon atoms to which they are connected. can,
and the fourth symbol Z, Y, R or R' indicates a direct connection to Sp))
Contains a filler mainly containing silica, at least one radical polymerization initiator, and a co-crosslinking agent selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds, and mixtures thereof. This is a rubber composition based on a crosslinked system.
Another subject of the invention is a rubber article, in particular a tread for a pneumatic or non-pneumatic tire, containing the composition according to the invention.

I - DEFINITIONS The term "composition based on" is to be understood as meaning a composition containing a mixture and/or the neat reaction product of the various components used; can and/or are intended to react with each other, at least in part, during the various stages of the manufacture of the composition, so that the composition is completely It becomes possible to achieve a partially crosslinked state or a non-crosslinked state.
For purposes of this invention, the phrase "parts by weight" (or phr) refers to parts by mass of elastomer. ) should be understood as meaning.
In this specification, all percentages (%) shown are percentages (%) by weight, unless explicitly stated otherwise.
Furthermore, any interval of values denoted by the phrase "between a and b" represents a range of values extending beyond a and less than b (i.e., the boundaries between a and b are excluded), whereas any interval of values denoted by the phrase "between a and b" Any interval of values denoted "a to b" means a range of values extending from a to b (ie, including the exact boundaries of a and b). In this specification, when a value interval is indicated by the phrase "a to b", an interval expressed by the phrase "between a and b" is also preferentially indicated.

When we refer to a "main" compound, this means that, for the purposes of the present invention, this compound is the predominant among the compounds of the same type in the composition, i.e. the largest of the compounds of the same type. It is understood to mean something that corresponds to mass. Thus, for example, the predominant elastomer is the elastomer that represents the largest mass relative to the total mass of elastomers in the composition. Similarly, a "major" filler is a filler that represents the largest mass of fillers in the composition. By way of example, in systems containing only one elastomer, the latter is predominant for purposes of the present invention; in systems containing two elastomers, the predominant elastomer accounts for more than half the mass of the elastomer. Equivalent to. On the other hand, a "minor" compound is a compound that does not represent the largest mass fraction among compounds of the same type. Preferably, the term "predominantly" is understood to mean present in more than 50%, preferably more than 60%, 70%, 80%, 90%, more preferentially " The main compound corresponds to 100%.

In this application, the phrase "all of the monomer units of a copolymer" or "the total amount of monomer units of a copolymer" means all constituent repeat units of said copolymer resulting from the insertion of monomers into the elastomer chain by polymerization. Unless otherwise indicated, the content of monomer units or repeat units in copolymers containing ethylene units and 1,3-diene units is given in molar percentages calculated on the basis of all of the monomer units of the copolymer.
The carbon-containing compounds described in this description may be of fossil or bio-based origin. In the latter case, they may be partially or completely biomass-based and may be obtained from biomass-derived renewable starting materials. This particularly concerns polymers, plasticizers, fillers, etc.
All values of glass transition temperature "Tg" described herein are determined in a known manner by DSC (Differential Scanning Calorimetry) according to standard ASTM D3418 (1999).

II - DESCRIPTION OF THE INVENTION II-1 Elastomeric Matrix The composition of the tire according to the invention contains a copolymer containing more than 50 phr of ethylene units and 1,3-diene units, wherein the ethylene units in the copolymer are the monomers of the copolymer. It has the essential feature of containing an elastomeric matrix representing more than 50 mol % of the units.
In the present specification, "a copolymer containing ethylene units and 1,3-diene units, in which the ethylene units in the copolymer correspond to more than 50 mol% of the monomer units of the copolymer", for the purpose of simplifying the expression, "copolymer" or It can be expressed as a "copolymer containing ethylene units and 1,3-diene units."
The term "elastomeric matrix" is intended to mean all elastomers of the composition.

The term "copolymer containing ethylene units and 1,3-diene units" is intended to mean any copolymer containing within its structure at least ethylene units and 1,3-diene units. Thus, the copolymers can contain monomer units other than ethylene units and 1,3-diene units. For example, the copolymers can also contain α-olefin units, especially α-olefin units having from 3 to 18 carbon atoms, advantageously from 3 to 6 carbon atoms. For example, the α-olefin units can be selected from the group consisting of propylene, butene, pentene, hexene or mixtures thereof.

In the known method, the phrase "ethylene units" refers to -(CH ₂ -CH ₂ )- units resulting from the insertion of ethylene into the elastomer chain.
In the known manner, the phrase "1,3-diene unit" refers in the case of isoprene to units derived from the insertion of a 1,3-diene by 1,4-addition, 1,2-addition or 3,4-addition. . The 1,3-diene unit is, for example, a 1,3-diene or a mixture of 1,3-dienes, the 1,3-diene having from 4 to 12 carbon atoms, for example very Specifically, they are 1,3-butadiene and isoprene. Preferably, the 1,3-diene is 1,3-butadiene.
Advantageously, the ethylene units in the copolymer represent between 50 mol% and 95 mol%, preferably between 55 mol% and 90 mol% of the monomer units of the copolymer.
Advantageously, the copolymer containing ethylene units and 1,3-diene units is a copolymer consisting of ethylene and 1,3-diene, ie said copolymer contains no other than ethylene and 1,3-diene. Contains no units.

If the copolymer is a copolymer of ethylene and 1,3-diene, it advantageously contains units of formula (III) and/or (IV). The presence of 1,2-cyclohexanediyl, a saturated six-membered ring unit of formula (III), as a monomer unit in the above copolymer is due to the rapid introduction of ethylene and 1,3-butadiene into the polymer chain during its growth. may originate from a unique insertion.

－ＣＨ₂－ＣＨ（ＣＨ＝ＣＨ₂）－ （ＩＶ）
例えば、エチレン及び１，３－ジエンからなるコポリマーは、式（ＩＩＩ）の単位を欠いていてよい。この場合、式（ＩＶ）の単位を含有することが好ましい。
エチレン及び１，３－ジエンからなるコポリマーが、式（ＩＩＩ）の単位又は式（ＩＶ）の単位、或いは式（ＩＩＩ）の単位及び式（ＩＶ）の単位を含有する場合、上記コポリマーにおける式（ＩＩＩ）の単位及び式（ＩＶ）の単位のモルパーセンテージは、それぞれｏ及びｐであり、好ましくは以下の式（式１）を満たし、より好ましくは式（式２）を満たし、ｏ及びｐは上記コポリマーの全てのモノマー単位に基づいて計算される。
０＜ｏ＋ｐ≦２５ （式１）
０＜ｏ＋ｐ＜２０ （式２）

-CH ₂ -CH (CH=CH ₂ )- (IV)
For example, a copolymer of ethylene and 1,3-diene may lack units of formula (III). In this case, it is preferable to contain a unit of formula (IV).
When the copolymer consisting of ethylene and 1,3-diene contains units of formula (III) or units of formula (IV), or units of formula (III) and units of formula (IV), the formula ( The molar percentages of the units of III) and the units of formula (IV) are o and p, respectively, preferably satisfying the following formula (formula 1), more preferably satisfying the formula (formula 2), where o and p are Calculated based on all monomer units of the copolymer.
0<o+p≦25 (Formula 1)
0<o+p<20 (Formula 2)

According to the invention, the copolymer, preferably consisting of ethylene and 1,3-diene (preferably 1,3-butadiene), is a random copolymer.
Advantageously, the number average mass (Mn) of said copolymer, preferably consisting of ethylene and 1,3-diene (preferably 1,3-butadiene), is between 100,000 and 300,000 g/mol, preferably between 150,000 and 250,000 g/mol. /mol.
The Mn of the copolymer is determined in a known manner by size exclusion chromatography (SEC) as described below.

The SEC (Size Exclusion Chromatography) technique makes it possible to separate macromolecules in solution according to their size through a column packed with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the bulkiest being eluted first. Although SEC is not an absolute method, it provides a molar mass distribution map of a polymer. The various number average molar masses (Mn) and weight average molar masses (Mw) can be determined from commercially available standards and the polydispersity index (PI=Mw/Mn) can be calculated by "Moore" calibration. . Polymer samples are not subjected to any specific treatment prior to analysis. The latter weighs approximately 1 g. It is simply dissolved in the elution solvent at a concentration of l ^-1 . The solution is then filtered through a filter with a porosity of 0.45 μm before injection. The equipment used is a Waters Acquity or Waters Alliance chromatography line. The elution solvent was tetrahydrofuran containing 250 ppm of BHT (butylated hydroxytoluene) antioxidant, and the flow rate was 1 ml. min ⁻¹ , column temperature is 35° C., and analysis time is 40 minutes. The columns used were a set of three Agilent columns with the trade name InfinityLab PolyPore. The volume of the injected sample solution is 100 μl. The detector is an Acquity or Waters 2410 differential refractometer and the software for processing the chromatographic data is the Waters Empower system. The calculated average molar mass is compared to a calibration curve made with polystyrene standards.

The copolymers can be obtained according to various synthetic methods known to those skilled in the art, depending in particular on the desired microstructure of the copolymers.
Generally, the above copolymers can be prepared according to known synthetic methods by copolymerization of at least 1,3-diene, preferably 1,3-butadiene, and ethylene in the presence of a catalyst system containing, in particular, a metallocene complex. As for catalyst systems based on this metallocene complex, the catalyst systems are described in the documents EP1092731, WO2004035639, WO2007054223 and WO2007054224 in the name of the applicant. The copolymers, even if they are random, can also be prepared by processes using preformed types of catalyst systems, such as those described in documents WO2017093654, WO2018020122 and WO2018020123.
The copolymers may consist of a mixture of copolymers containing ethylene and diene units that differ from each other on account of their microstructure and/or their macrostructure.
Advantageously, the content of copolymer containing ethylene units and 1,3-diene units in the composition is in the range from 60 to 100 phr, preferably from 80 to 100 phr.
The elastomer matrix can advantageously contain only copolymers containing ethylene units and 1,3-diene units as elastomers.

Alternatively, the elastomeric matrix can also contain diene elastomers other than copolymers containing ethylene units and 1,3-diene units (also referred to herein as "other elastomers"). The other elastomers, if present, are minor, ie, represent less than 50%, less than 40%, less than 30%, less than 20%, or even less than 10% by weight of the elastomer matrix. For example, the content of the other elastomer in the composition may be in the range of 0 to 40 phr, preferably 0 to 20 phr.
Other elastomers of the elastomer matrix of the tire according to the invention are preferentially highly unsaturated diene elastomers, such as polybutadiene (abbreviated "BR"), synthetic polyisoprene (IR), natural rubber (NR). , butadiene copolymers, isoprene copolymers and mixtures of these elastomers. "Highly unsaturated diene elastomer" shall mean a diene elastomer derived at least in part from a conjugated diene monomer having a content of diene-derived (conjugated diene) units, typically greater than 50% (mol%). be understood.

II-2 1,3-dipolar compound The rubber composition according to the invention contains a 1,3-dipolar compound. The term "1,3-dipole compound" is understood according to the definition set by IUPAC.
The above 1,3-dipole compound corresponds to formula (I).
Q-Sp-B (I)
(In the formula,
Q contains a dipole containing at least and preferably one nitrogen atom;
Sp is preferably a divalent atom or atomic group bonding Q to B,
B contains an imidazole ring corresponding to formula (II)

(II)
（式中、
４つの符号Ｚ、Ｙ、Ｒ及びＲ’のうちの３つは、同一であるか又は異なっており、それぞれ原子又は原子団を表し、Ｚ及びＹは、それらが連結する炭素原子と共に環を形成することができ（当然、ＺもＹも第４の符号を示さない場合）、
且つ第４の符号のみ、Ｓｐへの直接の連結を示す））

(II)
(In the formula,
Three of the four symbols Z, Y, R and R' are the same or different and each represent an atom or an atomic group, and Z and Y form a ring together with the carbon atoms to which they are connected. (of course, if neither Z nor Y shows the fourth sign),
and only the fourth sign indicates a direct connection to Sp))

According to a first alternative form of the invention, R indicates a direct linkage to Sp, in which case R is the fourth code.
According to this alternative form, R' may be a hydrogen atom or a carbon-based group which may contain at least one heteroatom.
According to a preferred embodiment of this alternative form, R' is a carbon-based group containing 1 to 20 carbon atoms, preferably an aliphatic group, more preferentially preferably 1 represents an alkyl group containing ~12 carbon atoms.

According to a second variant of the invention, R' indicates a direct linkage to Sp, in which case R' is the fourth symbol.
According to the first or second alternative, Z and Y can each be a hydrogen atom.
According to the first alternative or the second alternative, Z and Y together with the carbon atoms to which they are linked can form a ring. The ring formed by Z, Y, and the atoms to which Z and Y connect may be substituted or unsubstituted and may contain at least one heteroatom. Z and Y can form an aromatic ring with the two carbon atoms to which they are linked. In this case, the imidazole ring may be substituted or unsubstituted benzimidazole.

According to a third alternative form of the invention, Y or Z indicates a direct linkage to Sp, although of course if Y and Z do not form a ring with the carbon atoms to which they are linked, in which case where Y or Z is the fourth code.
According to a second or third variant of the invention, R advantageously represents a hydrogen atom or a carbon-based group which may contain at least one heteroatom. In this case R is a group of 1 to 20 carbon atoms, preferably an aliphatic group, more preferentially an alkyl group preferably containing 1 to 12 carbon atoms, more preferentially also a methyl group. It can be.

Advantageously, Sp is divalent.
Sp can be a group containing up to 20 carbon atoms, which group can contain at least one heteroatom. Sp may be an aliphatic group or an aromatic group.
When Sp is an aliphatic group, it preferentially contains 1 to 20 carbon atoms, more preferentially 1 to 12 carbon atoms, even more preferentially 1 to 6 carbon atoms. carbon atoms, very particularly 1 to 3 carbon atoms. When Sp is an aromatic group, it preferentially contains 6 to 20 carbon atoms, more preferentially 6 to 12 carbon atoms.
Advantageously, Sp has 1 to 20 carbon atoms, preferentially 1 to 12 carbon atoms, more preferentially 1 to 6 carbon atoms, even more preferentially 1 to 6 carbon atoms. It is a divalent group selected from alkylene groups containing 3 carbon atoms. More preferably still, SpO is a divalent group containing 1 to 3 carbon atoms, preferably a methylene group.
Arylene radicals containing preferably 6 to 20 carbon atoms, more preferentially 6 to 12 carbon atoms, may also be suitable as divalent radicals Sp.
Compounds selected from the group consisting of nitrile oxides, nitrile imines and nitrones are very particularly suitable as 1,3-dipole compounds, in which case Q is a -C≡N→O unit, -C≡N Contains →N- units or -C=N(→O)- units.
When Q contains a -C≡N→O unit, Q preferably contains a unit corresponding to formula (V), and more preferentially represents a unit corresponding to formula (V).

(V)
（式中、５つの符号Ｘ₁～Ｘ₅のうちの４つは、同一であるか又は異なっており、それぞれ原子又は原子団であり、且つ第５の符号は、Ｓｐへの直接の連結を示し、Ｘ₁及びＸ₅が共にＨ以外であることが知られている）５つの符号Ｘ₁～Ｘ₅のうちの４つは、脂肪族基であっても芳香族基であってもよい。上記脂肪族基は、１～２０個の炭素原子、優先的には１～１２個の炭素原子、より優先的には１～６個の炭素原子、より優先的には更に１～３個の炭素原子を含有することができる。上記芳香族基は、６～２０個の炭素原子、優先的には６～１２個の炭素原子を含有することができる。

(V)
(In the formula, four of the five symbols X ₁ to X ₅ are the same or different, each representing an atom or an atomic group, and the fifth symbol represents a direct connection to Sp. and it is known that both X ₁ and X ₅ are other than H) Four of the five symbols X ₁ to X ₅ may be aliphatic groups or aromatic groups. . Said aliphatic group has 1 to 20 carbon atoms, preferentially 1 to 12 carbon atoms, more preferentially 1 to 6 carbon atoms, more preferentially further 1 to 3 carbon atoms. It can contain carbon atoms. The aromatic group may contain 6 to 20 carbon atoms, preferentially 6 to 12 carbon atoms.

X ₁ , X ₃ and X ₅ are each preferentially an alkyl group of 1 to 6 carbon atoms, more preferentially an alkyl group of 1 to 3 carbon atoms, and is further a methyl group or an ethyl group.
Advantageously, X ₁ , X ₃ and X ₅ are the same. Furthermore, X ₁ , X ₃ and X ₅ are each preferentially an alkyl group of 1 to 6 carbon atoms, more preferentially an alkyl group of 1 to 3 carbon atoms, and more preferably Furthermore, it is a methyl group or an ethyl group.
Particularly advantageously, the 1,3-dipole compound is the compound 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl), corresponding to formula (Va) methyl)benzonitrile oxide, or the compound 2,4,6-triethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide corresponding to formula (Vb).

Ｑが－Ｃ＝Ｎ（→Ｏ）－単位を含有する場合、Ｑは、式（ＶＩ）又は（ＶＩＩ）に相当する単位を含有することができる。

When Q contains -C=N(→O)- units, Q can contain units corresponding to formula (VI) or (VII).

（式中、
Ｙ₁は、脂肪族基、優先的には、好ましくは１～１２個の炭素原子を含有するアルキル基であるか、又は６～２０個の炭素原子を含有する芳香族基、優先的には、アルキルアリール基、より優先的には、フェニル基又はトリル基であり、且つ
Ｙ₂は、Ｓｐへの直接の連結を含み、脂肪族基、優先的には、好ましくは１～１２個の炭素原子を含有するアルキレン基であるか、又は優先的には６～２０個の炭素原子を含有し、そのベンゼン環上にＳｐへの直接の連結を含む芳香族基である）

(In the formula,
Y ₁ is an aliphatic group, preferentially an alkyl group containing preferably 1 to 12 carbon atoms, or an aromatic group containing 6 to 20 carbon atoms, preferentially , an alkylaryl group, more preferentially a phenyl group or a tolyl group, and Y ₂ contains a direct linkage to Sp, preferentially an aliphatic group, preferably of 1 to 12 carbons. or is preferentially an aromatic group containing from 6 to 20 carbon atoms and containing a direct linkage to Sp on its benzene ring)

In this case, direct linkage of the benzene ring of Y ₂ to Sp is equivalent to stating that Sp is a substituent on the benzene ring of Y ₂ .
When Q contains -C=N(→O)- units, the 1,3-dipolar compound can be a compound of formula (VIa), (VIb), (VIIa) or (VIIb).

1,3-dipole compounds corresponding to formula (I) can be easily synthesized according to the synthetic process described in paragraph IV-2 below.
The amount of 1,3-dipole compound introduced into the rubber composition is expressed as molar equivalents of imidazole rings. For example, if the 1,3-dipole compound contains only one imidazole ring of formula (II) as defined above, 1 mole of imidazole ring corresponds to 1 mole of the 1,3-dipole compound. do. When the 1,3-dipolar compound contains two imidazole rings of formula (II) as defined above, 2 moles of imidazole rings correspond to 1 mole of the 1,3-dipolar compound. In the latter case, the use of said 1,3-dipolar compound corresponding to one molar equivalent of the imidazole ring corresponds to half a mole of the 1,3-dipolar compound.

According to the invention, the amount of 1,3-dipole compound in said composition is between 0 and 50 molar equivalents, preferably between 0.01 and 15 molar equivalents, per 100 moles of monomer units constituting said copolymer. It can be between. For example, it can be between 4 and 15 molar equivalents, such as between 5 and 15 molar equivalents. Preferentially, however, the amount of 1,3-dipolar compound in said composition is preferentially between 0 and 3 molar equivalents per 100 moles of monomer units constituting said copolymer. is between 0 and 2 molar equivalents, more preferentially even between 0 and 1 molar equivalent, even more preferentially even between 0 and 0.7 molar equivalent of the imidazole ring. These preferential ranges make it possible to more finely optimize the compromise between the hardness in the cured state and the hysteresis of the rubber composition according to its application, especially in tires. More preferably still, the amount of 1,3-dipolar compound in said composition is preferentially between 0.1 and 3 molar equivalents, more preferentially, per 100 moles of monomer units constituting said copolymer. between 0.1 and 2 molar equivalents, more preferentially even between 0.1 and 1 molar equivalents, even more preferably even between 0.1 and 0.7 molar equivalents of imidazole rings. .

II-3 Fillers The compositions according to the invention also have the essential feature of being based on fillers containing mainly silica.
The silica used in the composition according to the invention may be any silica known to the person skilled in the art, in particular those having both a BET specific surface area and a CTAB specific surface area of less than 450 m ² /g, preferably from 30 to 400 m ² /g, especially from 60 to 300 m 2 /g. ² /g. The silica advantageously has a BET specific surface area in the range from 125 to 200 m ² /g and/or a CTAB specific surface area in the range from 140 to 170 m ² /g.

The BET specific surface area of the above silica was determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938), and more specifically The method was adapted from the June 2010 standard NF ISO 5794-1, Annex E [Multi-point (5-point) volumetric method - Gas: Nitrogen - Degassing under vacuum: 1 hour at 160 °C - Relative pressure p/p ₀ range: 0.05-0.17].
The CTAB specific surface area values of the above silicas were determined according to the standard NF ISO 5794-1, June 2010, Appendix G. The process is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the "outer" surface of the filler.

All types of precipitated silicas can be used, especially highly dispersed precipitated silicas ("highly dispersed" or "highly dispersed silica" referred to as "HDS"). These precipitated silicas may or may not be highly dispersed and are well known to those skilled in the art. Mention may be made, for example, of the silicas described in the applications WO 03/016215 and WO 03/016387. In particular, among the commercially available HDS silicas, Evonik's Ultrasil® 5000GR silica and Ultrasil® 7000GR silica or Solvay's Zeosil® 1085GR silica, Zeosil® 1115 MP silica, Zeosil® osil( Zeosil® 1165MP silica, Zeosil® Premium 200MP silica and Zeosil® HRS 1200 MP silica can be used. Among the non-HDS silicas, the following commercially available silicas: Evonik's Ultrasil® VN2GR silica and Ultrasil® VN3GR silica, Solvay's Zeosil® 175GR silica, or PPG's Hi-Sil EZ120G (- D) Silica, Hi-Sil EZ160G (-D) silica, Hi-Sil EZ200G (-D) silica, Hi-Sil 243LD silica, Hi-Sil 210 silica and Hi-Sil HDP 320G silica can be used.
Advantageously, the filler contains more than 70% by weight, preferably more than 80% by weight of silica.

Preferably, the silica content is in the range of 5 to 60 phr, preferably 10 to 55 phr, more preferably 15 to 50 phr.
In order to bond the silica to the copolymer, at least two functional groups are added which are intended to provide sufficient bonding of chemical and/or physical properties between the silica (the surface of its particles) and the copolymer. A coupling agent (or binder) can be used in a known manner (hereinafter simply referred to as "coupling agent"). In particular, at least difunctional organosilanes or polyorganosiloxanes are used. The term "bifunctional" is understood to mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the copolymer. For example, such a bifunctional compound can contain a first functional group containing a silicon atom and a second functional group containing a sulfur atom, wherein the first functional group interacts with the hydroxyl group of the inorganic filler. The second functional group can interact with the copolymer.
Those skilled in the art will be aware of the following documents: WO02/083782, WO02/30939, WO02/31041, WO2007/061550, WO2006/125532, WO2006/125533, WO2006/125534, US6849754, WO99/09036, WO 2006/023815, WO2007/098080, Examples of coupling agents can be found in WO2010/072685 and WO2008/055986.

Although the use of a coupling agent is not essential, it is preferred. If a coupling agent is used, the content of coupling agent in the composition according to the invention is advantageously between 0.5% and 15% by weight, based on the weight of the silica. The amount of coupling agent can be easily adjusted by a person skilled in the art according to the content of reinforcing inorganic filler used in the composition of the invention.
Advantageously, the coupling agent is an organosilane selected from the group consisting of organosilane polysulfides, polyorganosiloxanes, mercaptosilanes, acrylosilanes and methacrylosilanes.
Compositions according to the invention can contain fillers other than silica, but this is not essential. These can in particular be organic fillers, such as carbon black.
The black that can be used in the context of the present invention can be any black conventionally used in pneumatic or non-pneumatic tires or their treads ("tire grade" black). Among the latter, more particularly reinforcing carbon blacks of the 100, 200 and 300 series, or blacks of the 500, 600 or 700 series (ASTM grades), such as N115, N134, N234, N326, N330, N339, N347, Mention may be made of N375, N550, N683 and N772 black. These carbon blacks can be used in isolated form as commercially available or in any other form, for example as a support for some used rubber additives. The carbon black may, for example, already be incorporated into the copolymer, in particular an isoprene copolymer, in the form of a masterbatch (see, for example, applications WO 97/36724 and WO 99/16600). Mixtures of several carbon blacks can also be used in certain amounts.

Advantageously, the carbon black is used in a content of 20 phr or less, more preferentially 10 phr or less (for example, the carbon black content is in the range 0.5 to 20 phr, especially 1 to 10 phr). ). Within the indicated interval, the coloring properties (black colorant) and UV stabilizing properties of the carbon black described above are effective and, furthermore, do not adversely affect the typical performance qualities provided by reinforcing inorganic fillers. do not have.
Preferably, the filler contains between 80% and 99% by weight of silica and between 1% and 20% by weight of carbon black.
II-4 Crosslinking System The composition according to the invention also comprises at least one radical polymerization initiator and a co-crosslinking system selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds and mixtures thereof. It contains a crosslinked system containing an agent.

Radical Polymerization Initiator The radical polymerization initiator is the source of free radicals necessary for the polymerization of the composition according to the invention. These compounds are well known to the person skilled in the art and are described in particular in the documents WO 2002/22688 and FR 2899808 and in the document Denisov et al. (Handbook of Free Radical Initiators, John Wiley & Sons, 2003).
Preferably, according to the invention, said at least one radical polymerization initiator is a group consisting of peroxides, azo compounds, redox (oxidation-reduction) systems and mixtures thereof, preferably peroxides, azo compounds. and mixtures thereof. More preferably, the at least one radical polymerization initiator is a peroxide or a mixture of several peroxides. The at least one radical polymerization initiator can be any peroxide known to those skilled in the art. Among peroxides well known to those skilled in the art, it is preferred in the light of the present invention to use organic peroxides.

The term “organic peroxide” is understood to mean an organic compound, ie a carbon-containing compound, containing an —O—O— group (two oxygen atoms linked by a covalent single bond). During the crosslinking process, the organic peroxide decomposes at its unstable O--O bonds, giving free radicals. These free radicals allow the formation of crosslinks.
The organic peroxide is preferably selected from the group comprising or consisting of dialkyl peroxides, monoperoxycarbonates, diacyl peroxides, peroxyketals and peroxyesters.
Preferably, the dialkyl peroxide is dicumyl peroxide, di(t-butyl) peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5- Dimethyl-2,5-di(t-amylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne, 2,5-dimethyl-2,5-di( t-Amylperoxy)hex-3-yne, α,α'-di[(t-butylperoxy)isopropyl]benzene, α,α'-di[(t-amylperoxy)isopropyl]benzene, di(t-amyl ) peroxide, 1,3,5-tri[(t-butylperoxy)isopropyl]benzene, 1,3-dimethyl-3-(t-butylperoxy)butanol and 1,3-dimethyl-3-(t-amylperoxy) ) selected from the group containing or consisting of butanol.

Some monoperoxy carbonates, such as OO-tert-butyl O-(2-ethylhexyl) monoperoxy carbonate, OO-tert-butyl O-isopropyl monoperoxy carbonate and OO-tert-amyl O-(2-ethylhexyl) monoperoxy Carbonates can also be used.
Among the diacylperoxys mentioned above, a preferred peroxide is benzoyl peroxide.
Among the above peroxyketals, preferred peroxides are 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl 4,4-di(t-butylperoxy)valerate, Ethyl 3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, 3,6,9-triethyl-3,6,9-trimethyl 1,4,7-triperoxy Nonane (or methyl ethyl ketone peroxide cyclic trimer), 3,3,5,7,7-pentamethyl 1,2,4-trioxepane, n-butyl 4,4-bis(t-amylperoxy)valerate, ethyl 3,3 - selected from the group containing or consisting of di(t-amylperoxy)butyrate, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-amylperoxy)cyclohexane and mixtures thereof be done. Preferably, the peroxy ester is selected from the group consisting of tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate and tert-butylperoxy-3,5,5-trimethylhexanoate.

In summary, the above organic peroxides are particularly preferably dicumyl peroxide, aryl or diaryl peroxide, diacetyl peroxide, benzoyl peroxide, dibenzoyl peroxide, di(tert-butyl) peroxide, tert-butyl cumyl peroxide, 2, 5-bis(tert-butylperoxy)-2,5-dimethylhexane, n-butyl 4,4-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate , tert-butylperoxyisopropyl carbonate, tert-butylperoxybenzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and their selected from the group consisting of mixtures. More preferably, the organic peroxide is dicumyl peroxide, n-butyl 4,4-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate, tert - from butylperoxyisopropyl carbonate, tert-butylperoxybenzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof selected from the group.

Examples of commercially available peroxides that can be used in the context of the present invention include Hercules Powder Co. Noury van der Lande's Perkadox Y12, Montecatini Edison S. p. A. Peroximon F40 of Noury van der Lande, Trigonox of Noury van der Lande, R. T. Vanderbilt Co. Varox or Wallace & Tiernan Inc. Luperko can be mentioned.
The term "azo compound" is understood to mean a compound whose molecular structure contains at least one -N=N- bond (two nitrogen atoms linked by a covalent double bond).
Preferably, the azo compound is 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-butanenitrile), 4,4'-azobis(4-pentanoic acid), 1,1 '-Azobis(cyclohexanecarbonitrile), 2-(t-butylazo)-2-cyanopropane, 2,2'-azobis[2-methyl-N-(1,1)-bis(hydroxymethyl)-2-hydroxy ethyl]propionamide, 2,2'-azobis(2-methyl-N-hydroxyethyl]propionamide, 2,2'-azobis(N,N'-dimethyleneisobutyramidine) dichloride, 2,2'-azobis( 2-amidinopropane) dichloride, 2,2'-azobis(N,N'-dimethyleneisobutyramide), 2,2'-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)-2 -hydroxyethyl]propionamide), 2,2'-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide), 2,2'-azobis[2-methyl-N- (2-hydroxyethyl)propionamide], 2,2'-azobis(isobutyramide) dihydrate, and mixtures thereof.

As an example of a commercially available azo compound that can be used in the context of the present invention, mention may be made of 2,2'-azobis(isobutyronitrile) from Sigma-Aldrich.
The term "redox system" is understood to mean a combination of compounds that causes a redox reaction that generates radicals.
They can be, for example, combinations of peroxides and tertiary amines (eg the pair of benzoyl peroxide and dimethylaniline), combinations of hydroperoxides and transition metals (eg the mixture of cumene hydroperoxide and cobalt naphthenate).
Advantageously, the content of radical initiator, preferably organic peroxide, in the composition according to the invention is between 0.1 and 10 phr, preferably between 0.1 and 3 phr, more preferably between 0.2 and 2. It is within the range of 5 phr.

The content of the radical polymerization initiator in the above composition is preferably between 1% by weight and 10% by weight, preferably between 1.25% and 8% by weight, preferably between 2% by weight, based on the weight of the co-crosslinking agent. % to 5% by weight, preferably between 3% and 4% by weight.
Co-crosslinker According to the invention, the co-crosslinker is selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds and mixtures thereof.
Preferably, the co-crosslinking agent contains a (meth)acrylate compound in the form of a metal salt, or an ester, or a polymer.

More preferably, the co-crosslinking agent contains an acrylate derivative of formula (VIII).
[X] _p A (VIII)
(In the formula,
[X]p corresponds to a group of formula (IX),

(IX)
（式中、
Ｒ₁、Ｒ₂及びＲ₃は、独立して、水素原子、又は直線状、分岐状若しくは環状のアルキル基、アルキルアリール基、アリール基及びアラルキルからなる群から選択されるＣ₁－Ｃ₈の炭化水素基を表し、１つ又は複数のヘテロ原子で割り込みされていてもよく、Ｒ₂及びＲ₃は共に非芳香族環を形成することができ、
（＊）は、式（ＩＸ）の基のＡへの連結点を表す）
Ａは、アルカリ土類金属若しくは遷移金属からなる群に属する原子、炭素原子、又は１つ若しくは複数のヘテロ原子で割り込み及び／若しくは置換されていてもよいＣ₁－Ｃ₃₀の炭化水素基を表し、
Ａは、ｐ個の自由原子価を含み、ｐは、２～６の範囲内の値を有し、
２～６個のＸ基は、同一又は異なると理解される）

(IX)
(In the formula,
R ₁ , R ₂ and R ₃ are independently hydrogen atoms, or C ₁ -C ₈ groups selected from the group consisting of linear, branched or cyclic alkyl groups, alkylaryl groups, aryl groups and aralkyl groups. represents a hydrocarbon group, optionally interrupted by one or more heteroatoms, R ₂ and R ₃ can together form a non-aromatic ring;
(*) represents the point of attachment of the group of formula (IX) to A)
A represents a C ₁ -C ₃₀ hydrocarbon group which may be interrupted and/or substituted with an atom belonging to the group consisting of alkaline earth metals or transition metals, a carbon atom, or one or more heteroatoms; ,
A contains p free valences, p has a value in the range from 2 to 6,
2 to 6 X groups are understood to be the same or different)

According to the invention, the bond between X and A may be an ionic bond or a covalent bond. Those skilled in the art will clearly understand that the bond between X and A is an ionic bond when A represents an atom belonging to the group consisting of alkaline earth metals or transition metals, in particular Zn or Mg. Furthermore, when A represents a carbon atom or a C ₁ -C ₃₀ hydrocarbon group, those skilled in the art will clearly understand that the bond between X and A is a covalent bond.
A cyclic alkyl group is understood to mean an alkyl group containing one or more rings.
A hydrocarbon group or a hydrocarbon chain interrupted by one or more heteroatoms is understood to mean a group or chain containing one or more heteroatoms, each heteroatom being between two carbon atoms of the chain, between a carbon atom of the group or the chain and another heteroatom of the group or the chain, or between two other heteroatoms of the group or the chain.

A hydrocarbon group or a hydrocarbon chain substituted with one or more heteroatoms is understood to mean a group or chain containing one or more heteroatoms, each heteroatom being It is bonded to the hydrocarbon group or chain by a covalent bond without interrupting the group or hydrocarbon chain.
The heteroatoms of A can be selected from the group consisting of oxygen, sulfur, nitrogen, silicon and phosphorous atoms and combinations thereof. Preferably, the heteroatoms of A are selected from the group consisting of oxygen and sulfur atoms. More preferably, the heteroatom of A is an oxygen atom.

In other words, A is advantageously one or more atoms selected from oxygen, sulfur, nitrogen, silicon or phosphorus atoms and combinations thereof, preferably selected from the group consisting of oxygen and sulfur atoms. Represents a linear, branched or cyclic C ₄ -C ₃₀ hydrocarbon group interrupted and/or substituted by a heteroatom. More preferably, A is advantageously interrupted and/or substituted by one or more oxygen and/or sulfur atoms, preferably interrupted and/or substituted by one or more oxygen atoms. , represents a straight, branched or cyclic, preferably straight or branched C ₄ -C ₃₀ hydrocarbon group.
Preferably, A is straight, branched or cyclic, preferably linear or interrupted with one or more oxygen and/or sulfur atoms, preferably one or more oxygen atoms. Represents a branched C ₄ -C ₃₀ hydrocarbon group. More preferably, A represents a straight or branched C ₄ -C ₃₀ hydrocarbon radical interrupted by one or more oxygen atoms.

If A represents a C ₄ -C ₃₀ hydrocarbon radical, it can be, for example, a C ₅ -C ₂₀ , preferably C ₆ -C ₁₆ hydrocarbon radical.
If A contains a cyclic hydrocarbon group, it may be a non-aromatic or aromatic cyclic hydrocarbon group.
The heteroatoms of the R ₁ , R ₂ , R ₃ and A groups can be, independently of each other, oxygen, sulfur, nitrogen, phosphorus or silicon atoms, preferably oxygen or nitrogen atoms.
Regardless of the nature of the above A groups, R ₁ , R ₂ and R ₃ can independently represent a hydrogen atom, a methyl group or an ethyl group, preferably R ₁ , R ₂ and R ₃ , each independently represent a hydrogen atom or a methyl group.
Advantageously, R ₁ can represent a methyl group and R ₂ and R ₃ can each represent a hydrogen atom. Alternatively, R ₁ , R ₂ and R ₃ can each represent a hydrogen atom.
The valence number p depends on the nature of the above A group. According to the invention p can be 2, 3, 4, 5 or 6. Preferably p is 2, 3 or 4, preferably 2 or 3, preferably 2.

Advantageously, irrespective of the R ₁ , R ₂ and R ₃ groups,
A represents an atom belonging to the group consisting of alkaline earth metals or transition metals, a carbon atom, or a C ₁ -C ₁₃ , preferably C ₁ -C ₈ hydrocarbon group;
A contains p free valences, p has a value in the range from 2 to 4,
The 2 to 4 X groups of the acrylate derivative of formula (VIII) are understood to be identical or different, preferably identical.
According to the invention, if A represents an atom belonging to the group consisting of alkaline earth metals or transition metals, it may be an atom selected from the group consisting of Zn and Mg, for example.
When A represents a C ₁ -C ₁₃ , preferably C ₁ -C ₈ hydrocarbon group, it can be, for example, a C ₁ -C ₇ , preferably C ₁ -C ₆ hydrocarbon group.
Preferably, A represents a C ₁ -C ₁₃ hydrocarbon group selected from the group consisting of the following groups:

（式中、ｍは、１～１３の範囲内の整数であり、（＊）は、Ａの式（ＩＸ）の基への連結点を表す）

(In the formula, m is an integer within the range of 1 to 13, and (*) represents the point of attachment of A to the group of formula (IX))

Advantageously, said C ₁ -C ₁₃ hydrocarbon group is a *-(CH ₂ ) _m -* group, where m is from 1 to 13, preferably from 1 to 8, preferably from 1 to 6 is an integer within the range of , and (*) represents the point of attachment of A to the group of formula (IX).
Therefore, according to the present invention, the acrylate derivatives of the above formula (VIII) include zinc dimethacrylate (ZDMA), magnesium dimethacrylate (MgDMA), zinc diacrylate (ZDA), magnesium diacrylate (MgDA), trimethacrylate It can be selected from trimethylolpropane acid (TMPTMA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA) and mixtures thereof.
Commercially available examples include diacrylate derivatives such as Cray Valley's Dymalink 633 which is zinc diacrylate (ZDA), Cray Valley's Dymalink 634 which is zinc dimethacrylate (ZDMA), and trimethylolpropane trimethacrylate (TMPTMA). SR351 from Sartomer, or 1,6-hexanediol diacrylate (HDDA) from Sigma-Aldrich.

Advantageously, the content of co-crosslinking agent, and preferably the total content of co-crosslinking agent, in the composition according to the invention ranges between 1 and 20 phr, preferably between 2 and 10 phr, preferably between 2 and 5 phr. It is within.
Advantageously, the amount of radical polymerization initiator in said composition is between 1% and 10% by weight, preferably between 1.25% and 8% by weight, relative to the weight of co-crosslinker in said composition. preferably between 2% and 5% by weight, preferably between 3% and 4% by weight.
Also advantageously, the ratio of the content of silica to the content of said co-crosslinking agent is in the range from 2 to 9, preferably from 3 to 7.
Sulfur Furthermore, the compositions according to the invention advantageously do not contain sulfur as a vulcanizing agent or contain less than 0.5 phr, preferably less than 0.3 phr, preferably less than 0.2 phr, preferably contains less than 0.1 phr. The sulfur may be molecular sulfur or may be derived from a sulfur donor such as alkylphenol disulfide (APDS).

II-5 Possible Additives The rubber composition may contain any or several conventional additives customarily used in elastomer compositions for tires, such as plasticizers (e.g. plasticizing oils and/or plasticizing resins), Pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described for example in the application WO 02/10269) may also be included.

II-6 Preparation of the Rubber Composition The composition according to the invention can be manufactured in a suitable mixer using two successive preparation steps well known to those skilled in the art.
The first stage of thermomechanical working or kneading (the "non-productive" stage) can be carried out in a single thermomechanical step, during which all necessary components, in particular the elastomeric matrix, fillers and any The various other additives, with the exception of the free-radical polymerization initiator, are charged to a suitable mixer, for example a standard internal mixer (eg of the "Banbury" type). Any filler can be incorporated into the elastomer in one or more portions during thermomechanical kneading. If the filler is already fully or partially incorporated into the elastomer in the form of a masterbatch, as for example described in the applications WO 97/36724 and WO 99/16600, it is a directly kneaded masterbatch; If appropriate, other elastomers or fillers present in the composition that are not in the form of a masterbatch, and also any other miscellaneous additives other than the radical polymerization initiator, are incorporated. The non-productive step may be carried out at elevated temperatures up to a maximum temperature of between 110°C and 200°C, preferably between 130°C and 185°C, usually for a time between 2 and 10 minutes.

The mechanically working second stage (the "productive" stage) lowers the temperature of the mixture obtained in the first non-productive stage, typically below 120°C, for example between 40°C and 100°C. After cooling to an external mixer, for example an open mill. The radical polymerization initiator is then incorporated and the combined mixture is then mixed for several minutes, for example 5 to 15 minutes.
Such steps are described, for example, in the applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO00/05300 or WO00/05301.

The final composition thereby obtained is then calendered, in particular in the form of sheets or slabs, in particular for laboratory characterization, or into rubber semi-finished products (or profile elements) which can be used, for example, as tire treads. (or coextruded with another rubber composition). These products can subsequently be used to manufacture tires according to techniques known to those skilled in the art.
Crosslinking of the above compositions can be carried out, for example, at temperatures from 130° C. to 200° C. and under pressure in a manner known to those skilled in the art.

Also described herein is a method for preparing a rubber composition according to the invention further comprising a crosslinking system, which method comprises the steps of:
During a first "non-productive" step, the copolymer, the 1,3-dipole compound and the filler are mixed thermomechanically until a maximum temperature of between 130°C and 200°C is reached. the step of adding;
cooling the combined mixture to a temperature below 100°C;
Subsequently, a step of incorporating the radical polymerization initiator,
and kneading the combined mixture to a maximum temperature of less than 120°C.
The amount of 1,3-dipolar compound added is preferentially between 0 and 3 molar equivalents, more preferentially between 0 and 2 molar equivalents, per 100 moles of monomer units constituting the copolymer. Preferentially still between 0 and 1 molar equivalent, even more preferably between 0 and 0.7 molar equivalent of imidazole rings. For each of these preferred ranges, the lower limit is preferably at least 0.1 molar equivalent of 1,3-dipole compound.

Advantageously, the 1,3-dipole compound is mixed with the copolymer before introducing the other components of the rubber composition, in particular before adding the filler. The contact time between the intimately mixed, especially thermomechanically kneaded, copolymer and the 1,3-dipole compound depends on the conditions of the mixing, especially thermomechanically kneaded, inter alia the temperature will be adjusted accordingly. The higher the temperature, the shorter this contact time. Typically, the contact time is 1 to 5 minutes for a temperature of 100°C to 130°C.
Preferably, at least one antioxidant is added to the copolymer, as is conventionally done, before it is introduced into the mixer, especially at the end of the synthesis of the copolymer.
After incorporation of all the components of the rubber composition, the final composition thereby obtained is then calendered and, in particular for laboratory characterization, e.g. in the form of sheets or slabs, or e.g. Extruded to form rubber profile elements used as rubber components for manufacturing.

II-7 Rubber Articles Another subject of the invention is rubber articles containing at least one composition according to the invention.
Considering the improved performance compromise in the light of the present invention, the rubber article is advantageously selected from the group consisting of pneumatic tires, non-pneumatic tires, caterpillar tracks and conveyor belts. Preferably, the rubber article is a pneumatic or non-pneumatic tire.
More particularly, another subject of the invention is a pneumatic or non-pneumatic tire with a tread containing at least one composition according to the invention.
Another subject of the invention is a rubber caterpillar track containing at least one rubber component containing at least one composition according to the invention, wherein said at least one rubber component is preferably an endless rubber belt, or a plurality of rubber tracks. It is a rubber pad, a rubber caterpillar track, and also a rubber conveyor belt containing the composition according to the invention.
The present invention relates to the above-described rubber articles both in the uncured state (i.e. before curing) and in the cured state (i.e. after crosslinking or vulcanization).

III - Preferred Embodiments In light of the above, preferred embodiments of the invention are described below.
1. A rubber composition comprising at least
an elastomeric matrix comprising a copolymer containing more than 50 phr of ethylene units and 1,3-diene units, wherein the ethylene units in the copolymer represent more than 50 mol% of the monomer units of the copolymer;
1,3-dipolar compound corresponding to formula (I),
Q-Sp-B (I)
(In the formula,
Q contains a dipole containing at least and preferably one nitrogen atom;
Sp is preferably a divalent atom or atomic group bonding Q to B,
B contains an imidazole ring corresponding to the following formula (II)

(II)
（式中、
４つの符号Ｚ、Ｙ、Ｒ及びＲ’のうちの３つは、同一であるか又は異なっており、それぞれ原子又は原子団を表し、Ｚ及びＹは、それらが連結する炭素原子と共に環を形成することができ、
且つ第４の符号Ｚ、Ｙ、Ｒ又はＲ’は、Ｓｐへの直接の連結を示す））
主にシリカを含有するフィラー、並びに
少なくとも１種のラジカル重合開始剤と、（メタ）アクリレート化合物、マレイミド化合物、アリル化合物、ビニル化合物及びそれらの混合物からなる群から選択される共架橋剤とを含有する架橋系をベースとした、ゴム組成物。

(II)
(In the formula,
Three of the four symbols Z, Y, R and R' are the same or different and each represents an atom or an atomic group, and Z and Y form a ring together with the carbon atoms to which they are connected. can,
and the fourth symbol Z, Y, R or R' indicates a direct connection to Sp))
Contains a filler mainly containing silica, at least one radical polymerization initiator, and a co-crosslinking agent selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds, and mixtures thereof. A rubber composition based on a crosslinked system.

－ＣＨ₂－ＣＨ（ＣＨ＝ＣＨ₂）－ （ＩＶ） 2. Composition according to embodiment 1, wherein the ethylene units in the copolymer represent between 50 mol% and 95 mol%, preferably between 55 mol% and 90 mol% of the monomer units of the copolymer.
3. Composition according to any one of embodiments 1-2, wherein the copolymer containing ethylene units and 1,3-diene units is a copolymer consisting of ethylene and 1,3-diene.
4. The composition according to any one of embodiments 1-3, wherein the 1,3-diene is 1,3-butadiene.
5. The composition according to any one of embodiments 1 to 4, wherein the copolymer contains units of formula (III) or units of formula (IV), or units of formula (III) and units of formula (IV). .

-CH ₂ -CH (CH=CH ₂ )- (IV)

6. The molar percentages of units of formula (III) and units of formula (IV) in the copolymer are o and p, respectively, and satisfy the following formula (formula 1), preferentially satisfy formula (formula 2), Composition according to any one of embodiments 1 to 5, wherein o and p are calculated based on all monomer units of the copolymer.
0<o+p≦25 (Formula 1)
0<o+p<20 (Formula 2)
7. The composition according to any one of embodiments 1 to 6, wherein the copolymer containing ethylene units and 1,3-diene units is a random copolymer.
8. Composition according to any one of embodiments 1 to 7, wherein the content of copolymer containing ethylene units and 1,3-diene units is in the range from 60 to 100 phr, preferably from 80 to 100 phr.
9. The composition according to any one of embodiments 1-8, wherein R' indicates a direct linkage to Sp.

10. The composition according to any one of embodiments 1-9, wherein Z and Y are each hydrogen atoms.
11. Composition according to any one of embodiments 1 to 9, wherein Z and Y together with the carbon atoms to which they are attached form a ring, preferably an aromatic ring.
12. According to any one of embodiments 1 to 11, R represents a hydrogen atom or a carbon-based group which may contain at least one heteroatom and preferably contains from 1 to 20 carbon atoms. Compositions as described.
13. Composition according to any one of embodiments 1 to 12, wherein R is an aliphatic group, preferentially an alkyl group, preferably containing from 1 to 12 carbon atoms.
14. The composition according to any one of embodiments 1-13, wherein R is methyl.
15. The composition according to any one of embodiments 1 to 14, wherein Sp is a group containing up to 20 carbon atoms, which may contain at least one heteroatom.

16. Sp is an aliphatic group containing preferentially 1 to 20 carbon atoms, more preferentially 1 to 12 carbon atoms, still more preferentially 1 to 6 carbon atoms; The composition according to any one of embodiments 1 to 15, wherein the composition is an aromatic group containing preferably 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms.
17. Sp contains 1 to 20 carbon atoms, preferentially 1 to 12 carbon atoms, more preferentially 1 to 6 carbon atoms, more preferentially a further 1 to 3 carbon atoms; or an arylene group preferentially containing from 6 to 20 carbon atoms, more preferentially containing from 6 to 12 carbon atoms, according to any one of embodiments 1 to 16. Composition of.
18. The composition according to any one of embodiments 1-17, wherein the 1,3-dipole compound is selected from the group consisting of nitrile oxides, nitrile imines, and nitrone.
19. Composition according to any one of embodiments 1 to 18, wherein Q contains -C=N→O units.
20. Composition according to any one of embodiments 1 to 19, wherein Q contains units corresponding to formula (V), preferably represents units corresponding to formula (V).

(V)
（式中、
５つの符号Ｘ₁～Ｘ₅のうちの４つは、同一であるか又は異なっており、それぞれ原子又は原子団であり、優先的には脂肪族基又は芳香族基であり、且つ第５の符号は、Ｓｐへの直接の連結を示し、Ｘ₁及びＸ₅が水素原子ではないことが知られている）
２１．Ｘ₁、Ｘ₃及びＸ₅が同一である、実施形態２０に記載の組成物。
２２．Ｘ₁、Ｘ₃及びＸ₅がそれぞれ１～６個の炭素原子、優先的には１～３個の炭素原子のアルキル基である、実施形態２０又は２１に記載の組成物。
２３．Ｘ₁、Ｘ₃及びＸ₅がそれぞれメチル又はエチルであり、好ましくはメチルである、実施形態２０～２２のいずれか１つに記載の組成物。

(V)
(In the formula,
Four of the five symbols X ₁ to X ₅ are the same or different, each is an atom or an atomic group, and is preferentially an aliphatic group or an aromatic group, and the fifth The symbol indicates a direct link to Sp, and it is known that X ₁ and X ₅ are not hydrogen atoms)
21. The composition according to embodiment 20, wherein X ₁ , X ₃ and X ₅ are the same.
22. A composition according to embodiment 20 or 21, wherein X ₁ , X ₃ and X ₅ are each an alkyl group of 1 to 6 carbon atoms, preferentially 1 to 3 carbon atoms.
23. A composition according to any one of embodiments 20 to 22, wherein X ₁ , X ₃ and X ₅ are each methyl or ethyl, preferably methyl.

24. The 1,3-dipole compound is 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide, or 2,4,6-triethyl-3 -((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide, preferably 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl) 24. The composition according to any one of embodiments 1-23, wherein the composition is methyl)benzonitrile oxide.
25. The content of the 1,3-dipolar compound is between 0 and 50 molar equivalents, preferably between 0.01 and 15 molar equivalents, for example between 4 and 15 molar equivalents, per 100 mol of monomer units constituting the copolymer. The composition according to any one of embodiments 1-24, wherein the composition is between molar equivalents.
26. The content of the 1,3-dipolar compound is between 0.1 and 3 molar equivalents, preferably between 0.1 and 2 molar equivalents, per 100 mol of monomer units constituting the diene elastomer; Even more preferentially between 0.1 and 1 molar equivalent of imidazole ring, even more preferentially between 0.1 and 0.7 molar equivalent. The composition described in.

27. Composition according to any one of embodiments 1 to 26, wherein the filler contains more than 70% by weight of silica, preferably more than 80% by weight of silica.
28. 28. The composition according to any one of embodiments 1-27, wherein the filler contains between 80% and 99% silica and between 1% and 20% carbon black.
29. Composition according to any one of embodiments 1 to 28, wherein the content of silica is in the range of 5 to 60 phr, preferably 10 to 55 phr, more preferably 15 to 50 phr.
30. further comprising a coupling agent for coupling said silica to said copolymer, said coupling agent preferably being an organosilane selected from the group consisting of organosilane polysulfides, polyorganosiloxanes, mercaptosilanes, acrylosilanes and methacrylosilanes. The composition according to any one of embodiments 1-29, wherein:

31. The composition according to any one of embodiments 1-30, wherein the radical polymerization initiator is selected from the group consisting of peroxides, azo compounds, redox (oxidation/reduction) systems, and mixtures thereof.
32. The above radical polymerization initiator is dicumyl peroxide, aryl or diaryl peroxide, diacetyl peroxide, benzoyl peroxide, dibenzoyl peroxide, di(tert-butyl) peroxide, tert-butylcumyl peroxide, 2,5-bis(tert-butyl peroxide). )-2,5-dimethylhexane, n-butyl 4,4'-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate, tert-butylperoxyisopropyl carbonate , tert-butylperoxybenzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof, preferably Dicumyl peroxide, n-butyl 4,4'-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate, tert-butylperoxyisopropyl carbonate, tert-butylperoxy an organic peroxide selected from the group consisting of benzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof The composition according to any one of embodiments 1-31, wherein the composition is:

33. Composition according to any one of embodiments 1 to 32, wherein the content of radical polymerization initiator is in the range from 0.1 to 3 phr, preferably from 0.2 to 2.5 phr.
34. The content of the radical polymerization initiator is between 1% by mass and 10% by mass, preferably between 1.25% and 8% by mass, preferably between 2% and 5% by mass based on the mass of the co-crosslinking agent. , preferably in the range between 3% and 4% by weight.

35. The composition according to any one of embodiments 1 to 34, wherein the co-crosslinking agent contains an acrylate derivative of formula (VIII).
[X] _p A (VIII)
(In the formula,
[X] _p corresponds to a group of formula (IX),

(IX)
（式中、
Ｒ₁、Ｒ₂及びＲ₃は、独立して、水素原子、又は直線状、分岐状若しくは環状のアルキル基、アルキルアリール基、アリール基及びアラルキルからなる群から選択されるＣ₁－Ｃ₈の炭化水素基を表し、１つ又は複数のヘテロ原子で割り込みされていてもよく、Ｒ₂及びＲ₃は共に非芳香族環を形成することができ、
（＊）は、式（ＩＸ）の基のＡへの連結点を表す）
Ａは、アルカリ土類金属若しくは遷移金属からなる群に属する原子、炭素原子、又は１つ若しくは複数のヘテロ原子で割り込み及び／若しくは置換されていてもよいＣ₁－Ｃ₃₀の炭化水素基を表し、
Ａは、ｐ個の自由原子価を含み、ｐは、２～６の範囲内の値を有し、
２～６個のＸ基は、同一又は異なると理解される）

(IX)
(In the formula,
R ₁ , R ₂ and R ₃ are independently hydrogen atoms, or C ₁ -C ₈ groups selected from the group consisting of linear, branched or cyclic alkyl groups, alkylaryl groups, aryl groups and aralkyl groups. represents a hydrocarbon group, optionally interrupted by one or more heteroatoms, R ₂ and R ₃ can together form a non-aromatic ring;
(*) represents the point of connection of the group of formula (IX) to A)
A represents a C ₁ -C ₃₀ hydrocarbon group which may be interrupted and/or substituted with an atom belonging to the group consisting of alkaline earth metals or transition metals, a carbon atom, or one or more heteroatoms; ,
A contains p free valences, p has a value in the range from 2 to 6,
2 to 6 X groups are understood to be the same or different)

36. In the acrylate derivative of the above formula (VIII),
A represents an atom belonging to the group consisting of alkaline earth metals or transition metals, a carbon atom, or a C ₁ -C ₁₃ hydrocarbon group,
A contains p free valences, p has a value within the range of 2 to 4,
Composition according to embodiment 35, wherein 2 to 4 X groups are understood to be the same or different.
37. The composition according to embodiment 35 or 36, wherein R ₁ , R ₂ and R ₃ independently of each other represent a hydrogen atom, a methyl group or an ethyl group.
38. The composition according to any one of embodiments 35 to 37, wherein R ₁ represents a methyl group and R ₂ and R ₃ each represent a hydrogen atom.

39. The composition according to any one of embodiments 35-37, wherein R ₁ , R ₂ and R ₃ each represent a hydrogen atom.
40. Composition according to any one of embodiments 35 to 39, wherein p is 2 or 3, preferably 2.
41. The composition according to any one of embodiments 35-39, wherein A represents an atom selected from the group consisting of Zn and Mg.
42. The composition according to any one of embodiments 35-39, wherein A represents a C ₁ -C ₁₃ hydrocarbon group selected from the group consisting of the following groups:

（式中、ｍは、１～１３の範囲内の整数であり、（＊）は、Ａの式（ＩＸ）の基への連結点を表す）
４３．共架橋剤の含有量が１～２０ｐｈｒ、好ましくは２～１０ｐｈｒ、好ましくは２から５ｐｈｒの間の範囲内である、実施形態１～４２のいずれか１つに記載の組成物。

(In the formula, m is an integer within the range of 1 to 13, and (*) represents the point of attachment of A to the group of formula (IX))
43. Composition according to any one of embodiments 1 to 42, wherein the content of co-crosslinker is in the range between 1 and 20 phr, preferably between 2 and 10 phr, preferably between 2 and 5 phr.

44. Composition according to any one of embodiments 1 to 43, wherein the ratio of the content of silica to the content of co-crosslinking agent is in the range from 2 to 9, preferably from 3 to 7.
45. Embodiment 1, wherein the composition does not contain molecular sulfur as a vulcanizing agent or a sulfur donor, or contains less than 0.5 phr, preferably less than 0.3 phr, more preferably less than 0.1 phr. 45. The composition according to any one of .
46. A rubber article containing a composition as defined in any one of embodiments 1-45.
47. 47. The rubber article of embodiment 46, wherein the article is selected from the group consisting of pneumatic tires, non-pneumatic tires, rubber caterpillar tracks, and conveyor belts.
48. A pneumatic or non-pneumatic tire containing a composition as defined in any one of embodiments 1-45.
49. A pneumatic or non-pneumatic tire according to embodiment 48, wherein a composition as defined in any one of embodiments 1-45 is present in the tread.

IV - EXAMPLE IV-1 Measurements and Tests Used Determination of Molar Mass: Size Exclusion Chromatography Analysis of Copolymers a) For copolymers soluble in tetrahydrofuran (THF) at ambient temperature, the molar mass was determined by size exclusion chromatography analysis in THF. Determined by graph. The sample was loaded into a series of Polymer Laboratories columns in 1 ml. Injection was performed using a Waters 717 injector and a Waters 515 HPLC pump at a flow rate of min ⁻¹ . This series of columns is placed in a chamber thermostatically held at 45°C and consists of:
1 PL Gel 5μm precolumn,
two PL Gel 5μm Mixed C columns,
One PL Gel 5μm-500Å column.

Detection was performed using a Waters 410 refractometer. Molar mass was determined by universal calibration with polystyrene standards certified by Polymer Laboratories and dual detection with a refractometer coupled to a viscometer.
Although not an absolute method, SEC makes it possible to understand the molar mass distribution of a polymer. Based on standard commercial products based on polystyrene, the various number average masses (Mn) and weight average masses (Mw) can be determined and the polydispersity index can be calculated (PI=Mw/Mn).
b) For copolymers insoluble in tetrahydrofuran at ambient temperature, the molar mass was determined in 1,2,4-trichlorobenzene. They were first dissolved under high temperature conditions (4 hours at 150°C) and then transferred in 1 ml onto a Waters Alliance GPCV 2000 chromatograph equipped with three Styragel columns (two HT6E columns and one HT2 column). Injection was performed at 150° C. with a flow rate of min ⁻¹ . Detection was performed using a Waters refractometer. Molar masses were determined by relative calibration with polystyrene standards certified by Polymer Laboratories.

Determination of Mole Fractions Detailed description of ¹ H NMR and ¹³ C NMR techniques specifically used in this application to determine the mole fractions of ethylene units, conjugated diene units and any trans-1,2-cyclohexane units. as "Investigation of ethylene/butadiene copolymers microstructure by ¹ H and ¹³ C NMR", Llauro MF, Monnet C., Barbotin F., Monteil V., Spitz R., Boisson C., Macromolecules 2001, 34, 6304-6311 The paper was referred to.
NMR Analysis Structural analysis and also determination of molar purity of the synthesized molecules was performed by NMR analysis. Spectra were obtained on a Bruker Avance 3400 MHz spectrometer equipped with a 5 mm BBFO Z-grad "broadband" probe. Quantitative ¹ H NMR experiments use a simple 30° pulse sequence and a 3 second repetition time between each of 64 acquisitions. The sample is dissolved in deuterated dimethyl sulfoxide (DMSO). This solvent is also used as a lock signal. Calibration is performed to a proton signal of 2.44 ppm deuterated DMSO against a TMS reference of 0 ppm. ¹ H NMR spectra combined with 2D ¹ H/ ¹³ C HSQC and ¹ H/ ¹³ C HMBC experiments allow structure determination of the molecules (see assignment table). Molar quantification is performed from quantitative 1D ¹ H NMR spectra.

Moony ML 1+4
Mooney plasticity measurements are performed according to standard ASTM D-1646 according to the following principles. A conventional uncured polymer is shaped into a cylindrical chamber heated to a predetermined temperature, typically 100°C. After 1 minute of preheating, the L-shaped rotor rotates in the test sample at 2 revolutions/min and the working torque to maintain this motion is measured after 4 minutes of rotation. Mooney plasticity (ML 1+4) is expressed in "Mooney units" (MU, 1 MU = 0.83 Newton meters).
Dynamic properties (after curing): Tensile tests These tensile tests make it possible to determine the elastic stress and break point properties. Unless otherwise indicated, they are carried out in accordance with the French Standard NF T 46-002 of September 1988. Processing the tensile records also makes it possible to plot the elastic modulus curve as a function of elongation. As used herein, modulus is the nominal (or apparent) secant modulus measured at initial elongation and is calculated by normalizing the initial cross section of the test sample. The nominal secant modulus (or apparent stress, MPa) is measured at 100% elongation and 300% elongation at initial elongation and is designated MSA100 and MSA300, respectively. Reinforcement index is the ratio of MSA300 modulus to MSA100 modulus, expressed in base 100 relative to control composition T1. Values greater than 100 represent improved reinforcement of the composition under consideration compared to the control composition.

The elongation at break (EB%) and stress at break (BS) tests are measured according to the standard NF ISO 37 of December 2005 for H2 dumbbell test specimens at a tensile speed of 500 mm/min. Elongation at break is expressed as a percentage of elongation. The breaking stress is expressed in MPa. These values are expressed on a base 100 relative to control composition T1. A value greater than 100 represents an improvement in the mechanical properties of the composition under consideration compared to the control composition.
All these tensile measurements are carried out under standard conditions of temperature (23±2° C.) and humidity measurements (50±5% relative humidity) according to the French standard NF T 40-101 (December 1979).

The dynamic properties G* and tan (δ) max were measured with a viscosity analyzer (Metravib VA4000) according to the standard ASTM D 5992-96. Samples of cross-linked compositions (4 mm thick and 400 mm cross-section ² ) reactions were recorded. Strain amplitude sweeps were performed from 0.15 to 50% (outward cycle) and then from 50 to 0.15% (return cycle). The results used are the nonlinearity (NL or ΔG*) and the loss factor tan(δ). The maximum observed value of tan(δ) is denoted tan(δ)max and is shown for the return cycle. Nonlinearity (NL or ΔG*) is the difference in shear modulus of loading between 0.15% and 50%, expressed in MPa. Nonlinearity and tan(δ)max are expressed on a basis of 100 relative to control composition T1. Values less than 100 represent the hysteresis and thereby improvement in rolling resistance of the composition under consideration compared to the control composition.
IV-2 Synthesis of 1,3-dipolar compound 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide This compound was synthesized using the following reaction scheme. It can be prepared according to the following.

IV. 2-1 Synthesis of 2-(chloromethyl)-1,3,5-trimethylbenzene This compound was synthesized by Zenkevich, IG; Makarov, AA; Russian Journal of General Chemistry; vol. 77; no. 4 (2007), pp 611 - 619 (Zhurnal Obshchei Khimii, Vol. 77, No. 4 (2007), pp. 653 - 662).

酢酸（２４０ｍｌ）中のメシチレン（１００．０ｇ、０．８３２ｍｏｌ）、パラホルムアルデヒド（２６．２ｇ、０．８７４ｍｏｌ）及び塩酸（２４０ｍｌ、３７％、２．９０６ｍｏｌ）の混合物を撹拌し、３７℃まで非常にゆっくりと（１．５時間）加熱する。大気温度まで戻した後、混合物を水（１．０ｌ）とＣＨ₂Ｃｌ₂（２００ｍｌ）で希釈し、生成物をＣＨ₂Ｃｌ₂（５０ｍｌで４回）で抽出する。有機相を合わせ、次いで水（１００ｍｌで５回）で洗浄し、１１～１２ｍｂａｒまでエバポレーションする（浴の温度＝４２℃）。無色油（１３３．５２ｇ、収率９５％）を得る。＋４℃で１５～１８時間後、油は結晶化した。結晶をろ取し、－１８℃に冷却した石油エーテル（４０ｍｌ）で洗浄し、次いで大気圧下、大気温度で３～５時間乾燥させる。融点３９℃の白色固体（９５．９ｇ、収率６８％）を得る。モル純度は９６％を上回る（１Ｈ ＮＭＲ）。

A mixture of mesitylene (100.0 g, 0.832 mol), paraformaldehyde (26.2 g, 0.874 mol) and hydrochloric acid (240 ml, 37%, 2.906 mol) in acetic acid (240 ml) was stirred and heated to 37°C. Heat slowly (1.5 hours). After returning to ambient temperature, the mixture is diluted with water (1.0 l) and CH ₂ Cl ₂ (200 ml) and the product is extracted with CH ₂ Cl ₂ (4×50 ml). The organic phases are combined, then washed with water (5 times 100 ml) and evaporated to 11-12 mbar (bath temperature = 42° C.). A colorless oil (133.52 g, 95% yield) is obtained. After 15-18 hours at +4°C the oil crystallized. The crystals are filtered off, washed with petroleum ether (40 ml) cooled to -18°C, and then dried under atmospheric pressure and temperature for 3-5 hours. A white solid (95.9 g, yield 68%) with a melting point of 39° C. is obtained. Molar purity is >96% (1H NMR).

IV. 2-2 Synthesis of 3-(chloromethyl)-2,4,6-trimethylbenzaldehyde This compound was synthesized by Yakubov, AP; Tsyganov, DV; Belen'kii, LI; and Krayushkin, MM, Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation); Vol. 40; No. 7.2 (1991), pp. 1427 - 1432 (Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya; No. 7 (1991), pp. 1609 - 1615) can be obtained following the procedure described in the paper.

A solution of 2-(chloromethyl)-1,3,5-trimethylbenzene (20.0 g, 0.118 mol) and dichloromethyl methyl ether (27.26 g, 0.237 mol) in dichloromethane (200 ml) was heated under argon. to a solution of TiCl ₄ (90.0 g, 0.474 mol) in dichloromethane (200 ml) at 17° C. over 10-12 minutes. After stirring for 15-20 minutes at 17-20° C., water (1000 ml) and ice (500 g) are added to the reaction medium. After stirring for 10-15 minutes, the organic phase is separated. The aqueous phase is extracted with CH ₂ Cl ₂ (3×75 ml). The combined organic phases are washed with water (4×100 ml) and evaporated under reduced pressure to give a solid (bath temperature=28° C.). The desired product (22.74 g) is obtained with a yield of 97%. Its melting point is 58°C. The molar purity estimated by ¹ H NMR is 95 mol%.

IV. 2-3 Synthesis of 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde

ＤＭＦ（１０ｍｌ）中の３－（クロロメチル）－２，４，６－トリメチルベンズアルデヒド（１０．０ｇ、０．０５１ｍｏｌ）及びイミダゾール（１０．４４ｇ、０．１２７ｍｏｌ）の混合物を８０℃で１時間撹拌する。

A mixture of 3-(chloromethyl)-2,4,6-trimethylbenzaldehyde (10.0 g, 0.051 mol) and imidazole (10.44 g, 0.127 mol) in DMF (10 ml) was stirred at 80° C. for 1 hour. do.

After returning to 40-50°C, the mixture is diluted with water (200ml) and stirred for 10 minutes. The precipitate obtained is filtered off, washed on the filter with water (4 times 25 ml) and then dried at ambient temperature. A white solid (7.92 g, 64% yield) with a melting point of 161° C. is obtained. The molar purity is 91% ( ¹ H NMR).

IV. 2-4 Synthesis of 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde oxime

An aqueous solution of hydroxylamine (809 g, 0.134 mol, 50% in water, Aldrich) in EtOH (10 ml) was added to 2,4,6-trimethyl-3-((2-methyl-1H-imidazole-) in EtOH (110 ml). 1-yl)methyl)benzaldehyde (20.3 g, 0.084 mol) at 40°C. The reaction medium is stirred for 2.5 hours at a temperature of 50-55°C. After returning to 23° C., the resulting precipitate is collected by filtration, washed twice with EtOH/H ₂ O (10 ml/15 ml) mixture on the filter, and dried under atmospheric pressure and temperature for 15-20 hours. . A white solid (19.57 g, yield 91%) with a melting point of 247° C. is obtained. Molar purity is >87% ( ^1H NMR).

IV. 2-5 Synthesis of 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide

A solution of NaOCl (4% active chlorine, Aldrich, 49 ml) in water was added to 2,4,6-trimethyl-3-((2-methyl-1H-imidazole) in CH ₂ Cl ₂ (280 ml) at 6° C. over 5 minutes. -1-yl)methyl)benzaldehyde oxime (8.80 g, 0.034 mol) dropwise. The temperature of the reaction medium is maintained between 6°C and 8°C. The reaction medium is subsequently stirred at 8° C. to 21° C. for 2 hours. Separate the organic phase. The organic phase is washed with water (3 times 50 ml). After concentration under reduced pressure (bath temperature = 22-23 °C, 220 mbar) petroleum ether (10 ml) was added, the solvent was evaporated to 8-10 ml and the solution was kept at -18 °C for 10-15 h. to obtain a precipitate. The precipitate was collected by filtration, washed on the filter with a CH ₂ Cl ₂ /petroleum ether (2 ml/6 ml) mixture, then with petroleum ether (2 x 10 ml), and finally at atmospheric pressure and temperature for 10-10 min. Let dry for 15 hours. A white solid (5.31 g, 61% yield) with a melting point of 139° C. is obtained.
Molar purity is >95 mol% ( ^1H NMR).

IV-3 Preparation of Compositions In the following examples, rubber compositions were prepared as described in Section II-6 above. In particular, these compositions are manufactured in the following manner. The elastomer, if appropriate, is a 1,3-dipole compound kneaded only with the elastomer at 110° C. for about 2 minutes, then the silica, coupling agent, co-crosslinking agent and also various other ingredients, peroxide. (Final filling degree: about 70% by volume). The thermomechanical work (non-productive phase) is then carried out in one step, which lasts approximately 5-6 minutes until a maximum "down" temperature of 160° C. is reached. The mixture thereby obtained is collected and cooled, then the peroxide is taken into a mixer (homofinisher) at 23 °C and everything is mixed for a suitable time (for example between 5 and 12 minutes) (productive stage) .

The compositions thereby obtained are subsequently calendered and prepared either in the form of rubber slabs (thickness in the range 2-3 mm) or thin sheets for the determination of their physical or mechanical properties. or in the form of a profile element which can be used directly after cutting and/or assembling to the desired dimensions, for example as a semifinished tire product, in particular as a tread.
Crosslinking is carried out at 150°C. The applied crosslinking time t' _c (90) is the time required to torque the composition to reach 90% of its maximum torque. The torque of the composition is determined according to the standard DIN 53529-Part 3 (June 1983) using a vibrating disc rheometer at 150°C. t' _c (90) is determined for each composition according to standard NF T 43-015. It varies from about 20 to 40 minutes depending on the composition.

IV-4 Testing of Rubber Compositions The purpose of the examples given below was to determine the performance compromise between reinforcement, breaking stress and rolling resistance of the composition according to the invention (C1) and the three control competitors (T1 to T3). It is to compare.
The compositions tested (in phr) and the results obtained are shown in Table 1.
The control compositions differ from composition C1 according to the invention in that they do not contain a 1,3-dipole compound and/or a co-crosslinker according to the invention.

The results shown in Table 1 above demonstrate that in compositions based on highly saturated diene elastomers crosslinked with peroxides, the particular combination of 1,3-dipole compound and co-crosslinking agent according to the invention It is shown that the reinforcement and rolling resistance of the article can be significantly improved while exhibiting an improved breaking stress compared to the control composition T1.
The composition according to the invention is useful in numerous applications in the field of pneumatic or non-pneumatic tires, especially in treads where a good compromise between performance in terms of reinforcement, breaking stress and rolling resistance is desired. .

Claims (15)

A rubber composition comprising at least
an elastomeric matrix comprising a copolymer containing more than 50 phr of ethylene units and 1,3-diene units, wherein the ethylene units in the copolymer represent more than 50 mol% of the monomer units of the copolymer;
1,3-dipolar compound corresponding to formula (I),
Q-Sp-B (I)
(In the formula,
Q contains a dipole containing at least and preferably one nitrogen atom;
Sp is preferably a divalent atom or atomic group bonding Q to B,
B contains an imidazole ring corresponding to the following formula (II)

(II)
(In the formula,
Three of the four symbols Z, Y, R and R' are the same or different and each represent an atom or an atomic group, and Z and Y form a ring together with the carbon atoms to which they are connected. can,
and the fourth symbol Z, Y, R or R' indicates a direct connection to Sp))
Contains a filler mainly containing silica, at least one radical polymerization initiator, and a co-crosslinking agent selected from the group consisting of (meth)acrylate compounds, maleimide compounds, allyl compounds, vinyl compounds, and mixtures thereof. A rubber composition based on a crosslinked system. A composition according to claim 1, wherein the copolymer containing ethylene units and 1,3-diene units is a copolymer consisting of ethylene and 1,3-diene. R' indicates a direct linkage to Sp, Z and Y are each a hydrogen atom, and R can contain a hydrogen atom or at least one heteroatom, preferably from 1 to 20 carbon atoms 3. A composition according to claim 1 or 2 representing a carbon-based group containing. Composition according to any one of claims 1 to 3, wherein Sp is a group containing up to 20 carbon atoms, which may contain at least one heteroatom. Composition according to any one of claims 1 to 4, wherein the 1,3-dipolar compound is selected from the group consisting of nitrile oxides, nitrile imines and nitrones. Composition according to any one of claims 1 to 5, wherein Q contains units corresponding to formula (V) and preferably represents units corresponding to formula (V).

(V)
(In the formula,
Four of the five symbols X ₁ to X ₅ are the same or different, and each is an atom or an atomic group, and is preferentially an aliphatic group or an aromatic group, and the fifth The symbol indicates a direct link to Sp, and it is known that X ₁ and X ₅ are not hydrogen atoms) The 1,3-dipole compound is 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide, or 2,4,6-triethyl-3 -((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide, preferably 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl) The composition according to any one of claims 1 to 6, which is methyl)benzonitrile oxide. The content of the 1,3-dipolar compound is between 0.1 and 3 molar equivalents, preferably between 0.1 and 2 molar equivalents, of imidazole rings per 100 mol of monomer units constituting the copolymer. The composition according to any one of claims 1 to 7, which is The radical polymerization initiator is dicumyl peroxide, aryl or diaryl peroxide, diacetyl peroxide, benzoyl peroxide, dibenzoyl peroxide, di(tert-butyl) peroxide, tert-butylcumyl peroxide, 2,5-bis(tert-butyl peroxide). )-2,5-dimethylhexane, n-butyl 4,4'-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate, tert-butylperoxyisopropyl carbonate , tert-butylperoxybenzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof, preferably Dicumyl peroxide, n-butyl 4,4'-di(tert-butylperoxy)valerate, OO-(t-butyl)O-(2-ethylhexyl) monoperoxy carbonate, tert-butylperoxyisopropyl carbonate, tert-butylperoxy an organic peroxide selected from the group consisting of benzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof The composition according to any one of claims 1 to 8, which is Composition according to any one of claims 1 to 9, wherein the content of radical polymerization initiator is in the range from 0.1 to 3 phr, preferably from 0.2 to 2.5 phr. Composition according to any one of claims 1 to 10, wherein the co-crosslinking agent contains an acrylate derivative of formula (VIII).
[X] _p A (VIII)
(In the formula,
[X]p corresponds to a group of formula (IX),

(IX)
(In the formula,
R ₁ , R ₂ and R ₃ are independently hydrogen atoms, or C ₁ -C ₈ groups selected from the group consisting of linear, branched or cyclic alkyl groups, alkylaryl groups, aryl groups and aralkyl groups. represents a hydrocarbon group, optionally interrupted by one or more heteroatoms, R ₂ and R ₃ can together form a non-aromatic ring;
(*) represents the point of attachment of the group of formula (IX) to A)
A represents a C ₁ -C ₃₀ hydrocarbon group which may be interrupted and/or substituted with an atom belonging to the group consisting of alkaline earth metals or transition metals, a carbon atom, or one or more heteroatoms; ,
A contains p free valences, p has a value in the range from 2 to 6,
2 to 6 X groups are understood to be the same or different) In the acrylate derivative of formula (VIII),
A represents an atom belonging to the group consisting of alkaline earth metals and transition metals, a carbon atom, or a C ₁ -C ₁₃ hydrocarbon group;
A contains p free valences, p has a value within the range of 2 to 4,
Composition according to claim 11, wherein 2 to 4 X groups are understood to be the same or different. The composition according to claim 11 or 12, wherein R ₁ , R ₂ and R ₃ independently represent a hydrogen atom, a methyl group or an ethyl group. Composition according to any one of claims 1 to 13, wherein the content of co-crosslinker is in the range between 1 and 20 phr, preferably between 2 and 10 phr, preferably between 2 and 5 phr. A pneumatic or non-pneumatic tire containing a composition according to any one of claims 1 to 14, preferably present in the tread of the tire.